In addition to doing a limited number of exercises for each muscle group, you also want to limit the sets and amount of resistance you use at each workout. (ironmanmagazine.com)
But this isn't due to 2 sets being a «magical» number of exercise sets. (anymanfitness.com)
If you have a pair of dumbbells and a bench, you can do an infinite number of exercises for every muscle group. (greatideas.people.com)